ipv6: fix the check when handle RA

d9333196(ipv6:  Allow accepting RA from local IP addresses.) made the wrong
check, whether or not to accept RA with source-addr found on local machine, when
accept_ra_from_local is 0.

Fixes: d9333196(ipv6:  Allow accepting RA from local IP addresses.)
Cc: Ben Greear <greearb@candelatech.com>
Cc: Hannes Frederic Sowa <hannes@redhat.com>
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ndisc.c

@@ -1151,9 +1151,9 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	/* Do not accept RA with source-addr found on local machine unless
 	 * accept_ra_from_local is set to true.
 	 */
-	if (!(in6_dev->cnf.accept_ra_from_local ||
-	      ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
-			    NULL, 0))) {
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+			  NULL, 0)) {
 		ND_PRINTK(2, info,
 			  "RA from local address detected on dev: %s: default router ignored\n",
 			  skb->dev->name);
@@ -1294,9 +1294,9 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	}
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
-	if (!(in6_dev->cnf.accept_ra_from_local ||
-	      ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
-			    NULL, 0))) {
+	if (!in6_dev->cnf.accept_ra_from_local &&
+	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+			  NULL, 0)) {
 		ND_PRINTK(2, info,
 			  "RA from local address detected on dev: %s: router info ignored.\n",
 			  skb->dev->name);